Krishna's book - the Bhagavad-gita

The Bhagavad-gita ("song of God")—the famous conversation between the warrior Arjuna and the Supreme Being, Krishna—posing as Arjuna’s charioteer—at the onset of the battle of Kurukshetra, circa 3200 B.C.

Krishna explains all the essential spiritual truths: the difference between the soul and the body, the difference between the soul and the Supreme Soul (God), the science of reincarnation, the nature of time, the ultimate goal of yoga, why different kinds of religion appeal to different kinds of people, and the ultimate purpose of human life.